Indicate the NsdServiceInfo attributes are only filled in for a resolved service.

 * to {@link DiscoveryListener#onServiceFound} and a service lost is notified on

 * {@link DiscoveryListener#onServiceLost}.

 *

 * <p> Once the peer application discovers the "Example" http srevice, and needs to receive data

 * from the "Example" application, it can initiate a resolve with {@link #resolveService} to

 * resolve the host and port details for the purpose of establishing a connection. A successful

 * resolve is notified on {@link ResolveListener#onServiceResolved} and a failure is notified

 * on {@link ResolveListener#onResolveFailed}.

 * <p> Once the peer application discovers the "Example" http service, and either needs to read the

 * attributes of the service or wants to receive data from the "Example" application, it can

 * initiate a resolve with {@link #resolveService} to resolve the attributes, host, and port

 * details. A successful resolve is notified on {@link ResolveListener#onServiceResolved} and a

 * failure is notified on {@link ResolveListener#onResolveFailed}.

 *

 * Applications can reserve for a service type at

 * http://www.iana.org/form/ports-service. Existing services can be found at

    }

    /**

     * Retrive attributes as a map of String keys to byte[] values.

     * Retrieve attributes as a map of String keys to byte[] values. The attributes map is only

     * valid for a resolved service.

     *

     * <p> The returned map is unmodifiable; changes must be made through {@link #setAttribute} and

     * {@link #removeAttribute}.